How to achieve the effect like the CPU usage record and memory usage record in the task manager

zhangli617

That is, the value of a certain data changes continuously with time, forming a continuously changing curve. And the curve only displays the data of the last 3 minutes

960088

Simple math problem?

SetTimer(), change every second, or milliseconds

72次灌水被抓

Timed redraw

zhangli617

Redraw, isn't it necessary to redraw every second? Who has examples?

ayasakura

How to solve the problem of flicker and efficiency
For example, it can be designed that the picture is moved forward, that is, when the next drawing is made, the same picture of the previous time is copied forward, and then only the points added later need to be drawn to consider the problem of data alignment.

zhangli617

Oh, and I want to display many graphs of different data in the same interface at the same time, will it affect the system speed

kkedward

Is it just a drawing?
Fetch data in real time and draw in real time? The news in the station gives you an example, sine wave ~

ayasakura

Can be encapsulated into a curve drawing class, and then start a thread for each curve drawn

2511718

I have written source code before.

Collect data through a timer, and then determine the relative coordinate position of the current point according to the ratio of this data, define a POINT[100] array, leave an element to store the current coordinate value, and then turn the current element value to The last 99 elements are moved in. Of course, the array elements should be moved as a whole, and the last one discarded is the same as the queue data structure. After all the elements are moved, then draw them out.

The drawn effect may flicker. Of course, double buffering will not be used.

hamnhamn3

Polyline POINT[100]
First switch to MemDC and then Bitblt comes out